Conference PaperPDF Available

METALLIC ARTIFACT REMNANTS IN A SHOCK-METAMORPHOSED IMPACT BRECCIA: AN EXTENDED VIEW OF THE ARCHEOLOGICAL EXCAVATION AT STÖTTHAM (CHIEMGAU, SE

Authors:
  • Institute for Interdisciplinary Science, Gilching
Conference Paper

METALLIC ARTIFACT REMNANTS IN A SHOCK-METAMORPHOSED IMPACT BRECCIA: AN EXTENDED VIEW OF THE ARCHEOLOGICAL EXCAVATION AT STÖTTHAM (CHIEMGAU, SE

METALLIC ARTIFACT REMNANTS IN A SHOCK-METAMORPHOSED IMPACT BRECCIA: AN
EXTENDED VIEW OF THE ARCHEOLOGICAL EXCAVATION AT STÖTTHAM (CHIEMGAU, SE-
GERMANY) B. Rappenglück1, M. Hiltl2, K. Ernstson3, 1Institute for Interdisciplinary Studies, D-82205 Gilching,
Germany (barbara.rappenglueck@evtheol.uni-muenchen.de, 2Carl Zeiss Microscopy GmbH, D-73447 Oberkochen,
(mhiltl@online.de), 3Faculty of Philosophy I, University of Würzburg, 97074 Würzburg, Germany
(kernstson@ernstson.de).
Introduction: In 2010 a routine archeological
excavation at the town of Chieming-Stöttham in the
Chiemgau region in Southeast Germany (Fig. 1)
revealed an exotic layer sandwiched between Neolithic
and a Roman occupation layer (Fig. 2). The exotic
diamictic (breccia) layer showed all evidence of a
deposition in a catastrophic event that was rapidly
attributed to the Chiemgau meteorite impact [1, 2, and
references therein] (Fig. 1) that happened in the Bronze
Age/Iron Age.
Fig. 1. Location map for the Stöttham archeological
excavation site within the roughly elliptically encircled
Chiemgau meteorite impact strewn field.
The ample occurrence of extreme destruction,
extreme temperatures and highest pressures including
impact shock effects (Fig. 4) proved incompatible with
an undisturbed colluvial depositional sequence as
postulated by archeologists and pedologists/geo-
morphologists [3]. Following their argumentation the
Bavarian Office for Geology (LfU) and the Bavarian
Monuments Preservation Office (BLfD) declared the
unparalleled Stöttham exposure as a normal colluvium
which continously developed since the end of the last
Ice Age and let it fill up and overbuild. A recent
inspection of the depot of archieved samples from the
excavation revealed a key to an unexpected scenario,
and we report highlighting results of both
archeological and meteorite impact relevance.
The Chiemgau impact event: In a roughly
elliptically shaped strewn field (Fig. 1) around 100
mostly rimmed craters with diameters between a few
meters and a few 100 meters occur. Exceptional and
relevant in the context of this paper is a rimmed
doublet crater at the bottom of Lake Chiemsee [1],
which was in detail mapped by echosounder
measurements. Apart from the craters and their distinct
morphology as revealed from precise Digital Terrain
Model (DTM) analyses, the impact strewn field shows
all and abundant evidence of impact signature as is
required within the impact research community
(impact melt rocks, impact glasses, shock
metamorphism like PDF and diaplectic glass - quartz
and feldspar, shatter cones, meteoritic matter [1, 2, 4-
8]).
The Stöttham exposure - early research: Because
of the short distance and the considerable size, the
Lake Chiemsee doublet crater was reasonably
considered the source for the Stöttham catastrophe
layer (Fig. 2), which is interpreted as impact ejecta
sustained by a big, now established Lake Chiemsee
tsunami [9]. A short overview of the archeological and
impact-related inventory is shown in Figs, 3, 4 and in
more detail described in [10].
Fig 4. Impact inventory from the diamictic catastrophe
layer: Corrosion by heat and/or nitric acid precipitation
(A); disintegrated and fractured cobbles (B); partly
melted silica limestone (C); shock in quartz: multiple
PFs and spots of diaplectic glass (D); carbonaceous,
metallic and glassy spherules (E); shock melt in
sandstone; black under crossed polarizers (F).
New investigations - shocked polymictic impact
breccias with remnants of metallic artifacts: The
new investigations focused on samples, which had
archeologically been termed "slags" but which, on
cutting them, proved to be polymictic melt rock
breccias of prevailing amphibolitic, quartzite, silica
limestone, and sandstones components (Fig. 5). The
melt rock character and breccias-within-breccias with
1334.pdf50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132)
up to three breccia generations fit well with the impact
scenario of the first Stöttham study. Iron and copper
fragments were particularly noticeable as components
of the breccias, which, in view of the initiation of the
archeological excavation, were to be regarded as
remains of artifacts.
Fig. 5. Left: Polymictic impact breccias (archeo-
logically termed "slag") from the Stöttham excavation.
Right: Remnants of metallic artifacts in the impact
breccia: iron, lead bronze, tin bronze.
A preparation of a total of six "slag" samples for
SEM-EDS analyses revealed as a surprise that the
particles originally regarded as copper (Fig. 5) were
apparently an alloy with a high lead content (Fig. 6,
Fig. 7), which gave them the character of a lead
bronze.
Fig. 6. SEM-EDS of copper-lead bronze (Fig. 5, upper
right). Cu and Pb are intimately mixed.
But also the finest fragments of a (normal) tin
bronze were detected (Fig. 5). Another unusual feature
was the EDS analysis of a larger iron fragment (Fig.
5), which practically consists of the purest iron (with a
few carbon percentages).
Fig. 7. SEM-EDS: Complex copper - lead mobiliz-
ation within the breccia matrix.
The formation of the breccia with the embedding of
the metal particles must have been a very complex
process, which must have led to the partial separation
of the metal components and their mobilization within
the silicate rock components and possibly enabled the
formation of a kind of lead glass (Fig. 7).
Shock metamorphism: All specimens examined
with thin sections and the polarization microscope
show more or less pronounced shock metamorphism
(Fig. 8). These include melt glass, often as a breccia
matrix for various mineral fragments, ballen structures
in combination with diaplectic silica glass, multiple
sets of PDF in quartz, and mosaicism and PDF in
hornblende.
Fig. 8. Photomicrographs of shock metamorphism in
impact breccias under discussion. With regard to co-
genetic melt components and shock effects the breccias
according to common nomenclature may be termed a
suevite. II: parallel light, XX: crossed polarizers.
Discussion and conclusions: The new investig-
ations demonstrate once more impressively that the
Stöttham archeological site had been involved in a
meteorite impact invent, the Chiemgau impact. The
original finding of a meteorite impact layer between
two archeological horizons was to be classified as
unique worldwide. From the point of view of both
archeology and impact research, the new analyses have
put the crown on it by revealing human objects and
impact shock intimately intertwined in the same
samples - a worldwide novelty. An upcoming more
exact dating of the Chiemgau impact, based on the
metallic components, will be a significant side effect of
these unusual samples and their investigation.
References: [1] Ernstson, K. et al. (2010) J.
Siberian Federal Univ., Engin. & Techn., 1, 72-103.
[2] Rappenglück, M.A. et al. (2017) Z. Anomalistik,
17, 235-260. [3] Völkel, J. et al. (2012) Z.
Geomorphologie, NF, 56(3), 371-386. [4] Hiltl, M. et
al. (2011) 42th LPSC, Abstract #1391. [5] Bauer, F. et
al. (2013) Met. & Planet. Sci., 48, s1, Abstract #5056.
[6] Rappenglück, M.A. et al. (2014) Proc. Yushkin
Memorial, Syktyvkar, Russia, 106-107. [7] Rappen-
glück, M.A. et al. (2013) Meteoritics & Planet. Sci..,
48, s1, Abstract #5055. [8] Ernstson, K. et al. (2014)
LPSC 45th, abstract #1200. [9] Ernstson, K. (2016)
47th LPSC, Abstract #1263.[10] Ernstson, K. et al.
(2012) Medit. Archaeology Archaeometry, 12/2, 249-
259.
1334.pdf50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132)
Article
Full-text available
Secondary craters in impacts on moon, planets and their moons are a well known phenomenon, which has been investigated many times. In the article commented by us here, the authors report on a crater strewn field in the American state of Wyoming, which is interpreted as a field of secondary craters of a so far unknown larger primary impact structure and as a first on Earth. We compare the Wyoming crater strewn field with the Chiemgau impact crater strewn field in SE Germany and find that both have nearly identical characteristics of virtually all relevant features, in terms of geometries and petrography. We conclude that the alleged Wyoming secondary crater field is a fiction and the craters attributable to a primary impact. The alleged evidence is very poor to easily refuted. A primary crater does not exist to this day. The negative free-air gravity anomaly referred to, but not even shown, is invalid for this purpose. The Bouguer gravity map shows no indication of a possible large impact structure. Also unsuitable is the use of asymmetries with elongations of assumed secondary craters with a very questionable corridor intersection for the ejecta. Of 31 craters surveyed as proven, 15 are circular (eccentricity 1) and more than half (19) have an eccentricity ≤1.2. Circular and elongated craters are intermixed. The evaluated crater axes may just as well originate in a multiple primary impact. Elongated craters may also result from doublets of overlapping craters that are no longer fresh, as described by the authors themselves. In their paper, the authors do not show a Digital Terrain Model with contour lines for any of the surveyed craters, but only aerial photos blurred by vegetation. A verification of the crater measurements with the deduced eccentricities and strike directions is impossible. Not a single topographic profile over even a single crater in the strewn field is shown, either from DTM data or from an optical leveling, which could have been accomplished in an instant given the relatively small craters. Grave is the misconception that such a large crater field of 90 km length with three separate clusters is not possible according to 20 years old model calculations. A primary impact with multiple projectiles could perhaps be conceivable under rare circumstances, which are described by the authors as not relevant. The alleged impossibility of such a large primary strewn field with referring to the known small impact fields of Morasko, Odessa, Wabar, Henbury, Sikhote Alin, Kaalijärv, and Macha is contradicted by the three larger impact strewn fields of Campo del Cielo, Bajada del Diablo (very likely), and Chiemgau, which are best described in the literature but are not mentioned by Kenkmann et al. with a single word. The comparison of the Wyoming strewn field with the Chiemgau impact crater strewn field of about the same size here in the commentary article proves the scientifically clearly much greater significance of the Chiemgau impact, which must be considered as currently the largest and most significant Holocene impact despite the rejection and ignoring in some parts of the so-called impact community.
Article
Full-text available
We use Schmieder and Kring's article to show how science still works within the so-called "impact community" and how scienti c data are manipulated and "rubber-stamped" by reviewers (here, e.g., C. Koeberl and G. Osinski). We accuse the authors of continuing to list the Azuara and Rubielos de la Cérida impact structures and one of the world's most prominent ejecta occurrences of the Pelarda Fm. in Spain 1 2 as non-existent in the compilation. The same applies to the spectacular Chiemgau impact in Germany, which has been proven by all impact criteria for several years. For the authors' dating list, we propose that the multiple impact of Azuara is included together with the crater chain of the Rubielos de la Cérida impact basin as a dated candidate for the third, so far undated impact markers in the Massignano outcrop in Italy.
  • M A Rappenglück
Rappenglück, M.A. et al. (2017) Z. Anomalistik, 17, 235-260. [3] Völkel, J. et al. (2012) Z.
  • N F Geomorphologie
  • M Hiltl
Geomorphologie, NF, 56(3), 371-386. [4] Hiltl, M. et al. (2011) 42th LPSC, Abstract #1391. [5] Bauer, F. et al. (2013) Met. & Planet. Sci., 48, s1, Abstract #5056.
LPSC 45th, abstract #1200
  • M A Rappenglück
Rappenglück, M.A. et al. (2014) Proc. Yushkin Memorial, Syktyvkar, Russia, 106-107. [7] Rappenglück, M.A. et al. (2013) Meteoritics & Planet. Sci.., 48, s1, Abstract #5055. [8] Ernstson, K. et al. (2014) LPSC 45th, abstract #1200. [9] Ernstson, K. (2016) 47th LPSC, Abstract #1263.[10] Ernstson, K. et al. (2012) Medit. Archaeology Archaeometry, 12/2, 249-259.